Summary On 05September 1996, the Cypriot bulk carrier PONTOPOROS, with a cargo of 27,332 tonnes of wheat, departed the Port of Sorel, Quebec, bound for Naples, Italy. After clearing a berth at the mouth of the Richelieu River, the PONTOPOROS swung around in preparation to head downstream in the St.Lawrence River, but she grounded on a shoal at the edge of the channel. At the time of the accident, the vessel was under the conduct of a pilot and was assisted by two tugs. The vessel sustained minor damage, but there was no pollution as a result of this accident. Ce rapport est galement disponible en franais. Other Factual Information Particulars of the Vessel On the evening of 05September 1996, the PONTOPOROS finished loading wheat at berth No.15 in the Port of Sorel. Two tugs took up positions alongside the vessel, the OMNI RICHELIEU forward and the OMNI ST.LAURENT aft. At approximately 2145, the vessel cleared the dock, assisted by the OMNI ST.LAURENT, which towed the ship out of the Port of Sorel.[1] At 2149, the order was given to put the main engine at half astern and, at 2150, speed was increased to full astern as the vessel entered the mouth of the Richelieu River.[2] The vessel swung to port in the St.Lawrence River, and at 2152, the main engine was stopped off berth No.14. From 2155 to 2158, the main engine speed was gradually increased from dead slow ahead to full ahead. The OMNI ST.LAURENT astern was ordered to pull to port, while the OMNI RICHELIEU forward was ordered to pull to starboard. When, at 2201, it was observed that the speed over the ground was negligible, the main engine was stopped, then briefly run at half astern, and then was stopped again. The vessel continued to swing to starboard and to move toward the middle of the St.Lawrence River. Speeds of dead slow ahead and slow ahead were ordered at 2205 and 2206, respectively, when the vessel centre line was almost perpendicular to the channel. Main engine speed was increased to half ahead, and at 2208, the OMNI ST.LAURENT cast off the after tow-line of the vessel. Full speed ahead and 20 degrees starboard helm were ordered; starboard movement continued. When the vessel came around to a heading of 055G at 2209, the OMNI RICHELIEU cast off the vessel's forward tow-line. The helmsman was ordered to steer 065G. The pilot called the Marine Communications and Traffic Services (MCTS) by radiotelephone to report the vessel's estimated time of arrival at the next calling-in point. Meanwhile, at about 2210, the PONTOPOROS grounded in position 4603.36'N, 07306.30'W, on a shoal at the edge of the channel. The vessel was on a heading of 063G, about two cable lengths north of buoy SN28.[3] With the assistance of the tugs MAGDELAN SEA and DUGA, the PONTOPOROS was refloated on 13September at 0533. No water ingress was found and Transport Canada allowed the vessel to leave Sorel on condition that she anchor in Sept-les Bay for a hull inspection. On 15September, an underwater inspection revealed only minor damage and the vessel departed for Naples. The MCTS log indicates that at 1545 on 05September 1996, the water level at Sorel was 0.77m above chart datum. Low under-keel clearance can affect the performance of the propeller and rudder. The current vector opposite the mouth of the Richelieu River, as indicated on Canadian Hydrographic Service (CHS) marine chart No.1312, flows parallel to the le de Grce course. Conduct of the vessel was by visual observation. The manoeuvre executed, which consists of swinging to head downstream in the St.Lawrence River, is that adopted by the pilots. A 10m isobath extends from the mouth of the Richelieu River to the entrance of the ship channel downstream of the port. The channel entrance is not marked. On 24August 1995, the bulk carrier VAKHTANGOV, with a draught of 10.21m, grounded in position 4603.76'N, 07306.76'W, while attempting a similar manoeuvre to depart from the same dock. The PONTOPOROS and the VAKHTANGOV grounded at the edge of the shoal, south-east of the 10m isobath.